Detection of low-photon-flux signals at microwave frequencies or at infrared wavelengths has various commercial applications, including communications, radar and LiDAR, and other remote sensing applications. Related art detectors may lack sensitivity or may be costly. Moreover, related art detectors may lack the capability to bridge the gap effectively between a photon-counting mode, and a mode in which the detector measures a mean photon flux rate, of a relatively high photon flux. In the case of low photon flux, related art detectors may also lack of the energy-resolving capability, i.e. measuring the photon energy of individual photons under detection.
Thus, there is a need for an improved photon detector.